1. Field of the Invention
The present invention relates to a device for forming a foamed product integral with trim cover assembly. In particular, the invention is directed to a foaming die device of the type which allows a three-dimensional trim cover assembly to be placed therein and allows a liquid foaming agent to be injected into the inside of such trim cover assembly, so that a foam padding is created by curing the liquid foaming agent and filed in the trim cover assembly, thereby forming a foamed product integral with the trim cover assembly, such as a headrest or armrest for instance.
2. Description of Prior Art
In general, a vehicle or automobile is provided with a cushiony support element for resiliently supporting a body or some body portions of seat occupant or passenger in a comfortable way, which includes a seat, a headrest, an armrest and so forth. Such cushiony support element is basically formed by a foam padding and a three-dimensional trim cover assembly covering the foam padding. Typically, to form that cushiony support element, there has been known a foaming process for forming a foamed product integral with trim cover assembly, which consists of the steps of: providing a three-dimensional trim cover assembly preformed in a predetermined shape (which conforms to an outer shape of headrest or armrest, for example); placing the trim cover assembly together with required frame element(s) in a given foaming die device; thereafter injecting a liquid foaming agent into an inside of the trim cover assembly; and curing the liquid foaming agent so as to create and fill a foam padding in the trim cover assembly, whereby a foamed product integral with trim cover assembly is produced, which has frame element(s) integrally provided therein (i.e. a resultant headrest with stays or a resultant armrest with frames, for example)
Let us now for example assume that a headrest with stay will be formed in the above-described process. First of all, prior to the foaming operation, a three-dimensional trim cover assembly is preformed by sewing together separate cover materials in a predetermined shape conforming to a headrest. In most cases, in the process of forming such trim cover assembly, at first, all the cover materials are sewn together, with their reverse surfaces exposed outwardly, while defining an opening at a given point, so as to provide a reversed state of three-dimensional trim cover assembly, with all its outer surfaces facing inwardly thereof, which has the foregoing opening defined therein. Thereafter, a local part of the outer surfaces disposed inwardly of so reversed trim cover assembly is drawn outwardly through such opening, and then, by completely drawing out all the outer surfaces through that particular opening, a whole of the trim cover assembly is reversed into a normal state where all the outer surfaces thereof show up outwardly. Next, a required headrest frame element having a pair of stays formed therewith is inserted through the opening into the inside of such normal state of trim cover assembly and placed in position therein, while projecting the pair of stays through respective two holes formed in the trim cover assembly to the outside, whereby is provided a basic headrest unit comprising the three-dimensional trim cover assembly and the headrest frame disposed therein, with the pair of stays projecting outwardly from the trim cover assembly.
Such basic headrest unit is then placed in a foaming die device, followed by injecting a liquid foaming agent into the inside of the trim cover assembly. At this step, there has been the problem that the liquid foaming agent is leaked out through the aforementioned opening.
To solve the foregoing problem, the prior invention disclosed in the Japanese Laid-Open Patent, Publication No. 9-11252, which has been assigned to the same assignee of the present invention, teaches a foaming die device provided with a closure element for forcibly causing the afore-said opening to close tight, thereby preventing leakage of a liquid foaming agent through that opening. In brief, according thereto, when the basic headrest unit is placed in the die device, a closure plate element is forcibly inserted in the opening so that both two lateral edges of the opening are stretched outwardly in a direction opposite to each other, whereupon the opening is deformed laterally and brought to close contact with all peripheral surfaces of the plate element. Thus, the opening itself is in a completely closed state to prevent the liquid foaming agent from being leaked out therethrough.
In the foregoing prior art, the foaming die device comprises a stationary die and a movable die, such that the movable die is movable toward and away from the stationary die so as to close and open the die device, thereby allowing a basic headrest unit to be placed between the two dies and allowing a resultant headrest to be taken out therefrom. However, the closure plate element is provided to the movable die, with the result that, after having placed the basic headrest unit in the stationary die, just prior to the movable die being engaged upon the stationary die, it is required on the worker's side to quickly and precisely insert the closure plate element in the foregoing opening in the basic headrest unit. At this step, in most cases, the worker can not easily insert the closure plate element in the opening and can hardly ascertain that the closure plate element is precisely inserted in the opening in a manner sufficient to prevent leakage of liquid foaming agent through the opening.
Additionally, when disengaging the movable die from the stationary die, it is required for the worker to use his or her much more force than usual to forcibly widen the opening and remove the closure plate element therefrom, which has been with the problem that the movable die can not be quickly disengaged from the stationary die.